New Thermally Broken rSTUD Lumber

Colorado-based Ec Manufacturing started making structural insulated panels (SIPs) about a year and a half ago. The company was studying 2009 building code and thinking about how to innovate their products, when someone decided the building industry could use a thermally broken lumber material. That led to the creation of rSTUD.

rSTUD is made with laminated veneer lumber and a polyurethane foam bound by a patent-pending structure pack process. The company says the insulated lumber has an R-value of 21.

Ec Manufacturing is testing the new product and in talks with companies about manufacturing and distributing. Pricing is expected to be about $0.87 per linear foot and should become available in the first quarter next year.

With Passive House and what seems to be a growing interest in insulated, airtight structures, I thought it would be great to hear from readers on the potential advantages and disadvantages, if any, to a product like rSTUD. Open up below, if you have a thought.

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18 Comments

i’m not sure we’d ever use these on a passivhaus project… you would still need a thick wall assembly, and won’t achieve it with a 2×6 in most of the country, maybe in san diego it would be feasible?

also, LVL and polyurethane don’t have small footprints, embodied energy of LVL is pretty significant. is the polyurethane water blown or HFC-245fa? if the latter, this product could never save enough energy to recoup the GWP.

Final product will be available in 2 x 6, 2 x 8, 2 x 10, 2 x 12 dimensions for passive housing applications. 4th generation blowing agents will mitigate any GWP concerns. Current passive house building practices use TJI which allow for LVL flange materials which is acceptable. As the sustainability director of Ec Manufacturing we are constantly look for ways to improve our product and reduce the impact to the environment.

yes, presently there are PH’s utilizing TJIs for walls. i’d still be more likely to go with a double stud wall or modified larsen truss over TJI or this product – cheaper, lower embodied energy, etc. i’m not a fan of LVLs.

Looks fabulously innovative and cool! But I’ve got 3 questions:1. How does 2×4 get R-21 in-stud?2. Assuming one uses 2×4 studs, making polyisocyanurate as your only option, what is the comparable LF cost to 2×6 standard wood studs with 5.5″ fiberglass?3. Is the system detailed and tested for lateral and seismic — what different detailing / anchoring is required?

R-21 is for 2 x 6 dimensions. Although we provide multiple dimensions of rSTUD™ we concentrated on 2 x 6, particularly as it relates to the R-Values required in the 2009 IECC.
The intent of the product is to encourage 2 x 6 construction with the thermal break on the interior of wall that cost compare favorable to 2 x 6 stick frame with an exterior thermal break.
The dates for a fully tested product will be announced at the NAHB Builders show in Janurary

This looks like a very innovative product. The price is a bit high, but at least less than double a normal 2×6. I’m also not sure how they are getting an R-21 rating in a 2×6? They would need about 3.5″ of the highest performing foam to come close and it doesn’t really look like that from the images.

I agree that this may not be a big seller for Passive Homes as they already need to provide much thicker walls and, in doing so, are already addressing thermal bridging in other, more cost effective ways. What it could have a huge impact on is the more standard builder that is building 2×6 walls and wants to improve their efficiency by switching to these in combination with a better insulation like blown-in cellulose. This could allow traditional stick builders to achieve the same performance as a SIP home, if not better with no change in their building methods.

Mark: I’m sure it’s something you’re working on but I’d love to see more information (without trade secrets of course) about the manufacture process and what the footprint looks like compared to similar substitutes. Also average lifetime energy savings vs. an identical average size house using wood 2x4s etc.

I am working on a house built to passive standards using ICF construction. I have wondered what to use to create a thermal break around window and door openings. The traditional method of framing such openings is to use 2 x 12 products of some sort. This just might be an answer.

Our testing will include the rSTUD™ for use as plate material. One thing to keep in mind is that for purposes of marketing we have shown a “naked” stud. The final product will be coated to increase strength. As the depth of the stud increases so does the foam. We intend to keep the amount of wood to a minimum.

I love the idea of eliminating thermal bridging, so this looks like it could be a nice product for that reason. Like Tlofft, however, I worry about the back end, when it becomes waste. Regular scrap wood is biodegradable and safe when burned. This product isn’t.

Interesting product. Great to see a MFR looking for feedback. I’m also wondering about its use as plate material, perhaps with a rectangular washer long enough to span the insulation. Seems electricians/ plumbers would be OK with this.

I’d like to see your photo show your product in an optimized framing application instead of traditional wasteful framing. With the increased cost of your studs, there would be added incentive to go this route.